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Alexei Wong, Arturo Figueroa, Marcos A. Sanchez-Gonzalez, Won-Mok Son, Oksana Chernykh and Song-Young Park

, Brouillard, Simpson, Hopman, & Abdollah, 2000 ). Heart rate variability (HRV), the beat-to-beat variation in R-R intervals, is a non-invasive tool for the evaluation of cardiac autonomic function. Compared to age-matched healthy individuals, patients with FM have an attenuated HRV which is associated with

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Alexei Wong and Arturo Figueroa

Cardiac autonomic nervous activity is a key determinant of cardiovascular health and prognosis ( Schwartz, La Rovere, & Vanoli, 1992 ). Cardiac autonomic function (CAF) is typically evaluated by heart rate variability (HRV), a noninvasive tool that provides indicators of the relative contributions

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Isao Saito, Koutatsu Maruyama, Tadahiro Kato, Yasunori Takata, Kiyohide Tomooka, Ryoichi Kawamura, Yuichi Uesugi, Yoshihiko Naito, Haruhiko Osawa and Takeshi Tanigawa

diseases. 7 There is evidence that low autonomic functions predict hypertension, 8 diabetes mellitus, 9 , 10 and the occurrence of CVD. 10 , 11 Several pathways have been proposed to explain these relationships, in which autonomic dysfunction contributes to sympathetic baroreflex sensitivity, 12

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Stephen H. Boutcher, Barbara J. Meyer, Gemma A. Craig and Lee Astheimer

The relationship between aging, physical activity, and vagal influence on the heart was assessed by measuring resting heart period variability in postmenopausal women. Participants were 14 aerobically trained women (mean age 55 ± 1.0 years) and 20 untrained women (mean age 59 ± 1.1 years). Participants lay for 25 min while heart period variability was assessed during spontaneous and paced breathing (7.5 breaths · min-1). Heart period variability was assessed through time series analysis (HPVts) of the interbeat interval. Results indicated I that the trained women had significantly (p < .05) lower supine resting heart rate than the untrained group. HPVts at high frequencies during spontaneous and paced breathing was greater for trained compared to untrained participants. Similarly, HPVts at medium frequencies during spontaneous and paced breathing was greater for trained compared to untrained participants. Also, rate pressure product of the trained group was significantly lower than for the untrained. These results extend prior research by showing that aerobically trained postmenopausal women possessed significantly elevated resting vagal influence on the heart compared to their untrained counterparts.

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Douglas R. Seals, Kevin D. Monahan, Christopher Bell, Hirofumi Tanaka and Pamela P. Jones

Tonic vagal modulation of cardiac period (R-R interval) decreases with advancing age, but is greater in middle-aged and older adults who habitually perform aerobic exercise compared with their sedentary peers. Cardiovagal baroreflex sensitivity also declines markedly with age in sedentary adults but only 50% as much in regularly exercising adults. In previously sedentary middle-aged and older adults, a 3-month program of moderate aerobic exercise increases cardiovagal baroreflex sensitivity by 25%. Tonic (basal) sympathetic nervous system (SNS) activity increases with advancing age in both sedentary and habitually exercising adults. Despite this, SNS b-adrenergic support of energy metabolism (resting metabolic rate-RMR) declines with age in sedentary individuals. However, SNS b-adrenergic support of RMR is maintained with age inenduranceexercise-trainedadultsandthereforeismuchgreaterinmiddle-aged and older individuals who exercise regularly compared with their sedentary peers. Thus, regular aerobic (endurance) exercise modulates selective age associated impairments in autonomic nervous system-physiological function.

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Haresh T. Suppiah, Chee Yong Low, Gabriel Choong and Michael Chia

performance and autonomic function when compared with a no-nap condition. In study 2: an acute afternoon nap in adolescent track-and-field student-athletes resulted in significant deterioration in 20-m sprint performance when compared with a no-nap condition. The most notable finding in the studies was the

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Hein A.M. Daanen, Robert P. Lamberts, Victor L. Kallen, Anmin Jin and Nico L.U. Van Meeteren

Heart-rate recovery (HRR) has been proposed as a marker of autonomic function and training status in athletes. The authors performed a systematic review of studies that examined HRR after training. Five cross-sectional studies and 8 studies investigating changes over time (longitudinal) met our criteria. Three out of 5 crosssectional studies observed a faster HRR in trained compared with untrained subjects, while 2 articles showed no change as a result of training. Most longitudinal studies observed a corresponding increase in HRR and power output (training status). Although confounding factors such as age, ambient temperature, and the intensity and duration of the exercise period preceding HRR make it difficult to compare these studies, the available studies indicated that HRR was related to training status. Therefore, the authors conclude that HRR has the potential to become a valuable tool to monitor changes in training status in athletes and less well-trained subjects, but more studies and better standardization are required to match this potential.

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Frederick S. Daniels and Daniel M. Landers

This study investigated heart rate (HE) and respiration functioning during rifle shooting to test hypotheses derived from Schwartz's (1979) systems and disregulation theory, and to compare biofeedback with verbal instruction in developing awareness and control of autonomic patterns. Male subjects (N = 8) were pretested to determine HE and respiration patterns affecting performance. They were then divided into two equal groups and given either auditory biofeedback or verbal instruction. The auditory-biofeedback group received continuous pattern feedback through earphones while the verbal instruction group received only presession instruction without feedback. Each group trained for five sessions of 40 shots each. Following training, two 40-shot sessions were conducted. A scaled interview was administered pre- and posttraining to determine awareness/control of autonomic functioning. Compared to the verbal instruction group, the results showed that the biofeedback group significantly improved performance and consistency of the desired pattern and had significantly greater awareness/control of the autonomic pattern. The results supported the systems and disregulation theory as well as the viability of biofeedback for altering imbalances within the systems.

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Justin P. Guilkey, Brandon Dykstra, Jennifer Erichsen and Anthony D. Mahon

Purpose:

This study examined heart rate recovery (HRR) and heart rate variability (HRV) following maximal exercise in lean (<85th percentile age- and sex-BMI percentile; n = 11 (♂=5; ♀=6); 10.1 ± 0.7 years) and overweight (≥85th age- and sex-BMI percentile; n = 11 (♂=5; ♀=6); 10.5 ± 1.2 years) children.

Method:

Participants completed a 10-min rest, followed by a graded exercise test to maximal effort. HRV, in the time and frequency domains, was assessed during rest and recovery. Also during recovery, one-minute HRR and the time constant of a monoexponential line of best fit (HRRt) were determined.

Results:

There were no significant differences in one-minute HRR and HRRt between the lean (56 ± 7 beats∙min-1 and 160.4 ± 80.1 s, respectively) and overweight (51 ± 16 beats∙min-1 and 141.1 ± 58.1 s, respectively) groups. There also were no significant interactions between groups from rest to recovery for any HRV variables. Root mean square of successive differences (RMSSD) and high frequency power (HF) during recovery was 2.05 ± 0.49 ms and 3.30 ± 1.02 ms2 in the lean children, respectively. In the overweight children, RMSSD and HF were 1.88 ± 0.65 ms and 2.94 ± 1.27 ms2, respectively.

Conclusion:

HRR and HRV findings suggest there are no differences in autonomic function during recovery from maximal exercise in lean and obese 8- to 12-year old children.

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Kaisu Marjut Kaikkonen, Raija irmeli Korpelainen, Mikko P. Tulppo, Hannu Sakari Kaikkonen, Marja Liisa Vanhala, Mika Antero Kallio, Sirkka M. Keinänen-Kiukaanniemi and Juha Tapani Korpelainen

Background:

Autonomic nervous system (ANS) dysfunction and obesity are intrinsically related to each other. In normal-weight subjects physical activity (PA) and fitness are related to cardiovascular autonomic regulation, providing evidence that aerobic training may improve ANS functioning measured by heart rate variability (HRV). The goal of this study was to investigate the association between lifetime PA, aerobic fitness and HRV in obese adults.

Methods:

Participants included 107 (87 females) volunteers (mean age 44.5 years, median BMI 35.7) who completed health and lifestyle questionnaires and measurements of maximal aerobic performance, anthropometry and 24 h HRV.

Results:

In the multivariate linear regression analyses, lifetime physical activity explained 40% of the variance in normal R-R intervals (SDNN). Each 1-category increase in the activity index increased SDNN by 15.4 (P = .009) and 24% of the variance in natural logarithmic value of ultra-low frequency power (P = .050). High measured VO2max explained 45% of the variance in natural logarithmic value of high-frequency power (P = .009) and 25% of the variance in low frequency/high frequency ratio (P < .001).

Conclusions:

Lifetime physical activity and aerobic fitness may reduce obesity-related health risks by improving the cardiac autonomic function measured by HRV in obese workingage subjects. This research supports the role of lifetime physical activity in weight management strategies and interventions to reduce obesity-related health risks.